| 时间 | 值 （%） | 世界排名 |
|---|---|---|
| 2016 | 60.6 | 137 |
| 2015 | 60.5 | 138 |
| 2014 | 60.3 | 138 |
| 2013 | 60.1 | 138 |
| 2012 | 59.8 | 137 |
| 2011 | 59.6 | 137 |
| 2010 | 59.4 | 135 |
| 2009 | 59.1 | 136 |
| 2008 | 58.8 | 136 |
| 2007 | 58.5 | 135 |
| 2006 | 58.1 | 135 |
| 2005 | 57.6 | 134 |
| 2004 | 57.1 | 136 |
| 2003 | 56.4 | 138 |
| 2002 | 55.8 | 140 |
| 2001 | 55.3 | 143 |
| 2000 | 54.8 | 144 |
| 1999 | 54.4 | 144 |
| 1998 | 54 | 142 |
| 1997 | 53.7 | 143 |
| 1996 | 53.5 | 143 |
| 1995 | 53.3 | 143 |
| 1994 | 53.2 | 139 |
| 1993 | 53 | 136 |
| 1992 | 52.9 | 133 |
| 1991 | 53 | 132 |
| 1990 | 53.1 | 129 |
| 1989 | 53.1 | 129 |
| 1988 | 53.1 | 127 |
| 1987 | 53.3 | 127 |
| 1986 | 53.4 | 126 |